1. Field
At least one example embodiment relates to a memory system and/or a refresh control method thereof, and more particularly, to a memory system with improved performance and/or refresh control method thereof.
2. Related Art
There has been large demand on large-capacity dynamic random access memory (DRAM) for mobile electronic products including smart phones. Generally, data stored in memory cells of semiconductor memory devices such as DRAM may be changed due to leakage current. Accordingly, a refresh is required to periodically recharge the data stored in the memory cells.
In addition, with the development of memory systems including semiconductor memory devices, the number of semiconductor memory devices included in a single module or memory system is increasing.
In refreshing a plurality of semiconductor memory devices included in a memory system, the same refresh operation is performed even if refresh characteristics of the semiconductor memory devices are different from each other. In other words, a refresh operation is performed on a plurality of semiconductor memory devices based on the refresh characteristic of the worst cell among a plurality of memory cells included in the semiconductor memory devices, and therefore, a refresh interval may be unnecessarily short for semiconductor memory devices having good refresh characteristics, which leads to an increase in power consumption.
Therefore, it is desired to perform refresh operations on a plurality of semiconductor memory devices based on different refresh characteristics, thereby increasing the performance of a memory system.